OICC Press Progress in Biomaterials 2194-0517 14 04 2025 12 30 Biogenically synthesized zinc oxide nanoparticles using Penicillium chrysogenum filter to combat methicillin-resistant Staphylococcus aureus (MRSA) and Cancer Cells 10.57647/pibm-2025-17326 EN Mohamed A. Fareid Clinical Laboratory Science Department, Applied Medical Science College, University of Ha’il, Hail 2440, Saudi Arabia Gamal M. El-Sherbiny Botany and Microbiology Department, Faculty of Science, Al-Azhar University, Cairo 11884, Egypt https://orcid.org/0000-0003-3968-0536 Mohamed H. Sharaf Botany and Microbiology Department, Faculty of Science, Al-Azhar University, Cairo 11884, Egypt Ahmed A. Radwan Botany and Microbiology Department, Faculty of Science, Al-Azhar University, Cairo 11884, Egypt Asmaa M. Hegazy Clinical Laboratory Science Department, Applied Medical Science College, University of Ha’il, Hail 2440, Saudi Arabia Rosilah Ab Aziz First Year of Health and Medical Colleges, Basic Sciences Department, University of Ha’il, Hail 2440, Saudi Arabia Fatma A. Hamada First Year of Health and Medical Colleges, Basic Sciences Department, University of Ha’il, Hail 2440, Saudi Arabia Journal Article 2025 12 30 Staphylococcus aureus is a major opportunistic pathogen that persistently colonizes approximately 20% of the human population. It is capable of causing diverse infections ranging from mild skin lesions to severe, life-threatening conditions. The emergence of methicillin-resistant S. aureus (MRSA) has complicated treatment strategies and intensified the search for alternative antimicrobial agents. This study presents a novel, eco-friendly biosynthesis of zinc oxide nanoparticles (ZnO-NPs) using the cell-free filtrate of Penicillium chrysogenum and investigates their antibacterial, anti-virulence, antioxidant, and anticancer activities. The synthesized ZnO-NPs were characterized using UV-Visible spectroscopy, high-resolution transmission electron microscopy (HR-TEM), dynamic light scattering (DLS), zeta potential and X-ray diffraction (XRD). Antibacterial efficacy was determined against MRSA isolates through MIC assays, while biofilm inhibition and virulence gene expression analyses were performed to assess anti-virulence activity. Antioxidant capacity was evaluated using DPPH and ABTS assays, and cytotoxicity against HepG2 and MCF-7 cancer cell lines was assessed using MTT assays. UV-Vis spectra exhibited a distinct absorption peak at 430 nm. HR-TEM analysis revealed predominantly spherical to slightly irregular ZnO-NPs with an average diameter of 43.17 nm (ranging 50-70.25 nm). The biosynthesized ZnO-NPs demonstrated strong antibacterial activity against MRSA, with MIC values between 125 and 250 µg/mL, and significantly inhibited biofilm formation. Moreover, they downregulated key virulence genes by 2.0 - 4.6-fold. The nanoparticles also exhibited notable antioxidant activity with IC₅₀ values of 205 µg/mL (DPPH) and 315 µg/mL (ABTS), as well as potent anticancer effects with IC₅₀ values of 13.74 ± 0.02 µg/mL (HepG2) and 19.12 ± 0.51 µg/mL (MCF-7). This study demonstrates, for the first time, the biosynthesis of ZnO-NPs using P. chrysogenum filtrate with multi-functional bioactivity, including antibacterial, anti-virulence, antioxidant, and anticancer properties. These findings highlight the potential application of biosynthesized ZnO-NPs as promising biocompatible agents for combating MRSA infections and certain cancer types, paving the way for sustainable nanotherapeutic development